The 1922 Four-speed P. and M.

THE policy of Phelon and Moore, Ltd., of Gleckheaton, Yorkshire, has been a year by year improvement of an originally exceltent layout;
startling modifications have always been avoided, unless they were proved necessary and practical by test. This year, however, the
innovations for 1922 are considerable. In the first place, reference must be made to the
four-speed gear box, first described in The Motor Cycle of August 25, 1921, page
729. A team equipped with these competed in the A.C.U. Six Days Trials with considerable success, and since this gear was described the
change speed lever has been considerably simplified in design. It will be remembered that two speeds are given by the well-known
selective clutch gear, and two additional gears by a dog clutch sear box. The standard gear ratios are 5.3, 7.8, 12, and 18 to 1, but
higher gear ratios can, of course, be supplied for a machine used exclusively as a solo mount.

Lengthened Stroke.

So far as the engine is concerned considerable alterations have been made. It has been realised that the P. and M. is, and will be,
largely used for sidecar work, and the engine size has consequently been increased to 84.1x100 mm. (555 c.c). The cylinder casting will
revert to the old pattern, with radiating fins at right angles to the centre line of the cylinder; the fins, however, are considerably
deeper, and they are now cast on the cylinder head, increasing the cooling surface. More room is also available above the cylinder head
for cooling purposes, while the frame lug adjacent to the cylinder also has been removed, increasing the air space. The engine is now
absolutely oil-tight, and has an exceptionally clean appearance, while the timing case is circular and contains a new and simplified
timing gear, there being only two gear wheels, of which the larger carries the double cam for inlet and exhaust valves, with a small
half-compression cam between them, which is brought into operation by an eccentrically mounted tongue worked by a small lever on the
outside of the timing case. The heel of this tongue also works the exhaust independently of the half-compression device.

The crank case has been increased in size, and the piston now dips down into it, receiving oil thrown up from the flywheels. A Best
mechanical pump driven off the camshaft delivers oil through a sight-feed on the tank to the engine, and the pipes now pass through the
tank, and are hidden from view. The valve rocker spindles are supported at both ends, and the whole timing gear is a very fine piece of
design. Clip-on spring protectors are fitted to the valve springs.

Modifications in the transmission have also been effected. The front chain case is of aluminium, while the rear case has been much
simplified.

The frame is composed exclusively of round tubes, and is exceedingly light; and, though the machine weighs about 12 lb. more than the
1921 model, the sidecar with which it is fitted is 25 lb. lighter, making the total weight of the outfit considerably less than the
previous model. The ratchet hand brake is retained, but has been moved to the off side of the machine. The same brake can also be
applied by means of a pedal working independently of the ratchet lever, while the front rim brake now has the shoe reversed, and has
been made more powerful. The front guard is in one piece with its valances, and is well splayed out at the rear.

Fully Equipped.

The equipment of the machine is particularly complete. A Brooks B500 cantilever saddle is fitted, while the lighting outfit consists of
Lucas acetylene lamps, the head and tail lamps being supplied by one generator for the side lamp, and a licence holder is also provided.
Points of convenience and appearance have been well studied, as the control wires pass through the handle-bars, and the new tank holds
two gallons of petrol and 3¼ pints of oil. The ground clearance is 10 in. from the crank case, and 5½ in. from the footrests.

The sidecar is, of course, produced by the makers, and is considerably improved in construction and bodywork. Lugs incorporated in the
motor cycle frame serve as points of attachment for the chassis connections, and the latter do not require adjustment to attain good
alignment. Now that the capacity of the engine is increased in conjunction with the four speeds, the outfit should be capable of going
anywhere.